2. Field of the Invention
The present invention generally relates to munitions employing materials which need to be ignited or detonated to attain proper function and, more particularly, is concerned with a fiber optic pressure sensor for safing and arming a fuze used to ignite or detonate the munition.
2. Description of the Prior Art
Munitions which contain materials that need to be ignited or detonated to attain proper function typically have a safing and arming arrangement operable to ensure that arming of the munition fuze does not occur inadvertently, but rather only at a desired moment. A fuze is considered "armed" generally when an explosive train is "in line", that is, when the detonator is in position to initiate the booster charge or main charge of the munition. Examples of these types of munitions may include high explosive, shaped charge, illumination, and smoke projectiles.
Preferably, the intent of using a safing and arming arrangement is to provide a munition which only functions under a narrowly defined set of conditions, for example, the conditions which exist when the munition is propelled from its launcher. These environmental conditions can be used to arm the fuze.
A conventional type of a launcher is a projectile-firing device, composed essentially of a projectile-guide tube incorporating a reaction chamber in which chemical energy of a propellant is rapidly converted into heat. The hot gases produced expand to expel the projectile at a high velocity The reaction of the propellant produces the conditions which can be used to arm the fuze. The environmental conditions which the projectile is subjected to include setback (the high acceleration of launch), pressure, heat, noise, light and spin (if the launcher is rifled).
A need still remains for a way to utilize the pressure produced by the igniting and burning propellant as a primary or secondary safing environment for a fuze.